Highly efficient metal halide substituted CH3NH3I(PbI2)1-x(CuBr2)x planar perovskite solar cells

By substitution of some part of PbI2 to CuBr2 in CH3NH3PbI3 perovskite film, we fabricated inverted indium tin oxide (ITO)/poly(3,4-ethlened ioxythiop he ne): poly( styrenesulphonic acid) (PEDOT: PSS)/CH3NH3I(PbI2)(1-x)(CuBr2)(x) (x=0, 0.025, 0.050, 0.075, and 0.100)/Phenyl-C61-butyric acid methyl ester (PCBM)/LiF/Al planar perovskite solar cells via solvent dripping process. Whereas the Pbl(2)-DMSO2 (DMSO:dimethyl sulfoxide) intermediate is not flowable during heat-treatment process due to the simultaneous melting and decomposition, the CuBr2-DMSO2 intermediate is flowable so that the CH3NH3I(PbO2)(1-x)(CuBr2)(x) perovskite could form larger crystalline grains more reproducibly than the MAPbI(3) film. From the capacitance-voltage (C-V) characteristics and density functional theory (DFT) calculation, we could know that the conductivity of MAPbI(3) is much enhanced by CuBr2 substitution of PbI2 due to enhance charge carriers. Accordingly, the inverted CH3NH3I(PbI2)(1-x)(CuBr2)(x) (x=0.050) planar perovskite solar cells showed greatly improved device efficiency (average of 50 sample = 16.17 + 0.79 %, best = 17.09 %) than the efficiency of MAPbI(3) device (average of 50 sample = 12.02 + 0.86 %, best = 13.18 %) and did not show significant current density-voltage (J-V) hysteresis with respect to the scan direction. (C) 2016 Elsevier Ltd. All rights reserved.